This projects's objective is to design evaluate a surface accessibility measurement device that can quantitatively measure characteristics of a surface which correlate with its degree of accessibility to wheelchair users. Four surface accessibility measurement devices will be designed, fabricated and tested. Existing surface measurement devices, including penetrometers, will also be evaluated. A system for measuring the actual resistance a wheelchair encounters when traveling over a given surface will be fabricated as a reference for the other devices. A wide range of surfaces will be measured with all of the devices, including varieties of indoor carpeting, concrete, dirt, gravel and sand. The data obtained with existing and proposed devices will be compared to the data obtained with the system for measuring surface resistance to wheelchair movement. The measuring device(s) which best correlate(s) with the resistance of a standard wheelchair on a variety of surfaces will be identified. The development of a surface accessibility measurement device that is reliable over a wide range of surfaces will enable experts to disclose the degree of accessibility of indoor and outdoor surfaces. People with mobility limitations, designers and planners will use this information to determine the degree of accessibility of indoor and outdoor environments.